In connection with his defense of the federal Partial Birth Abortion Ban Act (or PBABA), Attorney General John Ashcroft recently sought to procure the medical records of 45 patients at a Chicago hospital. He contended that because he sought the records without patient identification, privacy concerns were not implicated.

But last week, a divided three-judge panel of the U. S. Court of Appeals for the Seventh Circuit disagreed. It held that the Justice Department is not entitled to the patients' medical records, even with their names and identifying information removed.

Judge Richard Posner's opinion for the appeals court in Northwestern Memorial Hospital v. Ashcroft is, for the most part, a carefully reasoned exegesis of some fairly technical bodies of federal law. But buried within the legal analysis is a novel--and to my mind, persuasive--account of the value of privacy.

In his opinion, Judge Posner explains that anonymity and privacy are not identical. Thus, though the women's records would have been anonymous, the court still deemed their production a privacy violation.

The State and Federal Partial Birth Abortion Ban Acts

To understand the litigation that gave rise to this opinion, consider how the federal PBABA arose.

In the 1990s, many states enacted legislation banning what they called "partial birth abortion." (The laws typically defined the phrase to refer to a method of abortion in which a second or third trimester fetus partially exits the womb before being destroyed.)

These laws were challenged on a number of grounds and, in the 2000 case of Stenberg v. Carhart, the U.S. Supreme Court held the Nebraska version unconstitutional. The Court's prior precedents had established that the government must permit even late-term abortions when they are medically necessary for the pregnant woman. And, as Justice Stephen Breyer explained for the majority, there are circumstances in which "partial birth" is the safest means by which a medically necessary abortion can be performed. Thus, the statute's failure to include an exception for medical necessity was fatal, and it was struck down as unconstitutional.

Ordinarily, when the Supreme Court interprets the Constitution, its word is final. The people can only supersede the Court by amending the Constitution.

Yet in 2003, in response to the Court's decision in the Nebraska case, Congress passed the federal Partial Birth Abortion Ban Act. Congress defended its decision to pass the very same kind of law that the Court had just struck down by arguing that it had made new factual findings.

According to Congress, the Court's factual premises were wrong in the Nebraska case. And in the federal statute, Congress made contrary findings. It found that "partial-birth abortion is never necessary to preserve the health of a woman, poses significant health risks to a woman upon whom the procedure is performed, and is outside of the standard of medical care."

The Lawsuit Seeking to Block the Federal PBABA

Immediately after President Bush signed the PBABA, a group of abortion providers sued to block it. They sought an injunction to stop the law from being enforced, and a federal district judge in New York City granted the injunction.

The plaintiffs also moved for "summary judgment"--a pre-trial disposition by the judge that is typically granted when there are no material facts in dispute, so that one side prevails simply as a matter of law. In support of their motion, the plaintiffs cited the Nebraska decision, Stenberg v. Carhart.

That decision said that the Constitution requires a health exception in a partial birth abortion ban. The plaintiffs pointed out that the federal act lacks such an exception as well. Thus, they urged the judge to hold that there was no need for a trial.

But just two weeks ago, the judge denied their motion. He did so on the ground that a trial was necessary to resolve the question whether the Supreme Court's view of the facts still prevails, in light of the contrary Congressional findings in the 2003 statute.

Against that backdrop, the government had sought the medical records of 45 patients at Northwestern Memorial Hospital. Presumably, it has sought these records to show that Congress's 2003 findings on "partial birth" abortions are correct, and the contrary findings of the Supreme Court in Stenberg are wrong.

More specifically, the government said it needed the records to challenge the testimony of one of the plaintiffs' experts, Dr. Cassing Hammond. Dr. Hammond plans to testify that in his experience "partial-birth" abortions are sometimes medically necessary. The government apparently seeks to cross-examine him using anonymous patient records from particular "partial birth" abortions.

The Court of Appeals' Decision: No Right Even to Anonymous Patient Records

Because Northwestern Memorial Hospital is in Illinois, the Justice Department's efforts to obtain its medical records were routed through the federal district court in Chicago. (Although the case was taking place in federal district court in New York, the subpoena was required to be issued by a federal court in the same judicial district as the hospital.)

The district judge quashed the subpoena for the records. And, as noted above, last week's ruling by the appeals court, authored by Judge Posner, affirmed that decision. Thus, the hospital, as of now, need not provide the government with the patients' medical records.

In the course of reaching its decision, the Court of Appeals first rejected a number of arguments for quashing the subpoena, which I will not detail here. Nevertheless, the appeals court reached the same bottom line that the district court had. It grounded its judgment in Federal Rule of Civil Procedure 45(c)(A)(iv), which authorizes judges to quash any subpoena that "subjects a person to undue burden."

Privacy Versus Anonymity: Did the Subpoena Impose An "Undue Burden"?

To determine whether the subpoena imposed an undue burden, the court weighed the burden of compliance against the utility of the information sought.

First, the court considered the burden of compliance. At first glance it might seem slight: All the hospital needed to do was to photocopy 45 sets of medical records with the names and other identifying facts (such as birthdays and social security numbers) blacked out. That sounds like about a day's work for a file clerk.

But the court reasoned that compliance with the subpoena would entail a different kind of burden. Judge Posner thought it might be possible for "skillful 'Googlers,' sifting the information contained in the medical records concerning each patient's medical and sex history, [to] put two and two together, 'out' the 45 women, and thereby expose them to threats, humiliation, and obloquy." That seems doubtful, however, because as Judge Manion pointed out in his dissent, the redacted medical records are subject to a protective order, so that the information would never make it to the web. (A document is "redacted" when information -- in this case, identifying information -- is whited or blacked out before it is produced in litigation.)

Nonetheless, Judge Posner pointed to another sort of burden that is not so readily dismissed. He explained that the 45 patients will have their privacy violated--even if their identities would not be revealed.

He provided the following analogy: "Imagine if nude pictures of a woman, uploaded to the Internet without her consent though without identifying her by name, were downloaded in a foreign country by people who will never meet her. She would still feel that her privacy had been invaded." Patients whose redacted late-term abortion records were produced in discovery, Posner suggested, would feel violated in the same way.

Amending Posner's Analogy: Are Faceless Nude Pictures Still a Violation?

Part of the power of Judge Posner's analogy stems from the fact that the woman's face might be recognized, or she might fear that images on what is after all a world-wide web would eventually find their way back to people who know her.

So let's amend Judge Posner's example by supposing that her face were obscured. I suspect that some women (or men) would not consider this a privacy violation. But, on the other hand, a great many would be horrified at the prospect of strangers using their admittedly anonymous images to fuel masturbatory fantasies.

Of course, the analysis of abortion records by expert witnesses, lawyers, and judges is not nearly so lurid. Nonetheless, one can well imagine that quite a few of the 45 women whose abortion records were revealed would be anguished to learn that details they thought they were sharing only with their doctor, were now receiving such scrutiny from strangers unconnected with the medical profession, and hostile to their right to receive a late-term abortion.

Perhaps recognizing that the privacy claims in the actual redacted abortion records are not quite so strong as in his analogy, Judge Posner acknowledged that the womens' privacy interest could be overcome by a government showing that the records would yield highly probative evidence.

But the government, he held, failed to make sure a showing. Indeed, he thought that the government had utterly failed, after repeated opportunities, even to explain how the records would be used to shed light on the necessity and efficacy of various methods of abortion.

Judge Posner thought it possible that the records, combined with other information, might shed such light, but he called the government to task for failing to explain how. Judge Manion made a plausible argument that the government had done so. Interested readers can compare the majority and dissent to see who has the better of the argument.

The Opinion's Most Interesting Holding: Anonymity Is Not the Same as True Privacy

To me, the most interesting aspect of the majority opinion is its recognition of a privacy interest independent of anonymity.

This is consistent with, though hardly the principal example of, the common law tort of invasion of privacy. To use a close variant on Judge Posner's example, suppose a peeping Tom catches a glimpse of a woman in the nude, but neither knows the woman's identity nor sees her face. In most jurisdictions, the peeping Tom would be liable for invasion of privacy.

I doubt that many people would disagree with this result. That is true in part because we see no reason to give the peeping Tom--who is, after all, a creep--a break. But it may also be true because we realize that even though the woman was anonymous, her privacy was nevertheless violated.

It is easy to lose sight of this intuition--that anonymity does not ensure privacy--in crafting public policy for other contexts. In an era when nearly all of our private information can be obtained by Judge Posner's enterprising Googlers, there is a temptation to settle for anonymity, and forget about privacy. If we must provide our most intimate details to doctors or health insurance managers, let us do it as numbers rather than people, we say. Of course, anonymous disclosure is better than complete exposure. Yet Judge Posner reminds us that anonymity is at best a substitute for privacy. It's not the real thing.

Michael C. Dorf is Professor of Law at Columbia University. His new book, Constitutional Law Stories, is published by Foundation Press, and tells the stories behind fifteen leading constitutional cases.